Ingestion of oral glucose modifies amino acid metabolism. Thus, oral or intravenous glucose lowers arterial amino acid levels. Our research aims are designed to better understand the underlying mechanisms. Two series of experiments are in progress: (A) Human -when man ingests a protein meal, there follows a rather prolonged rise in arterial amino acids. We have quantified splanchnic output of amino acids after a beef meal in normal subjects undergoing hepatic vein catheterization. When subjects ingest beef and one hour later have 100 g of glucose, splanchnic amino acid output drops precipitously. Thus suggests that glucose is acting either at the level of the bowel (e.g., via absorption) or at the hepatic level (B) Dog Studies - similar studies have been made in the conscious dog whose artery, hepatic and portal vein have been catheterized. Our results indicate that hypertonic glucose (but not glucose in an isotonic solution) slows amino acid absorption from the bowel.